When performing steel plate rolling and bending of higher strength steels, you will have two main considerations:
1. The tonnage/capacity of the machine
2. The spring back of the material after pressure is released
The tonnage is fairly linear in proportion with the yield strength. So if the yield strength doubles, so does the tonnage required to bend it. Most bending and rolling machines are rated using a “standard” of mild steel A36 or 1018 with yield strength around 36,000 psi.
Here are some typical grades specified for bending and rolling:
Grade TYPICAL Yield strength Tonnage Multiplier
A572Gr.50 50,000psi x 1.38
A588 Corten 50,000psi x 1.38
A516Gr.70 38,000 psi x 1.19
AR400 100,000psi x 2.78
Note that these are typical or even minimum properties.
You will have to look at the MTR (Material Test Report) from the producing mill to verify the actual properties of the metal you are trying to bend.
The spring back of the material is a more complicated formula, but in general:
1. The higher the yield strength, the more that the material springs back
2. The larger the forming radius, the more the spring back angle
For example, when you bend ¼” plate to a ¼” radius 90 degrees,
A36 will springback is only 0.25 degrees.
Gr50 will springback still is only 0.35 degrees.
But if the radius is larger, say 2”, then
A36 will springback 2.58 degrees.
Gr50 will springback 3.58 degrees.